Purpose: To evaluate the anti-oxidant and anti-neuroinflammatory effects of the Sargassum thunbergii extract (Mertens ex Roth) Kuntze (STE) in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells in vitro.

Methods: STE antioxidative activity was evaluated with an Electron Spin Resonance (ESR) spectrometer, which measured 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity. Cell viabilities were estimated using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assays. LPS-stimulated BV-2 microglia were used to study the expression and production of inflammatory mediators, such as nitric oxide (NO), inducible NO synthase (iNOS) and tumor necrosis alpha (TNF-α).

Results: LPS treatment, following STE pretreatment, decreased NO production by 13 ~ 65% in a dose-dependent manner (p < 0.001 at 20, 40, 80 and 100 μg/mL), and was associated with the down-regulation of inducible nitric oxide synthase (iNOS) expression. STE also attenuated the TNF-α soluble protein by 16 ~ 47% (p < 0.01at 20, 40 and 80 μg/mL) in activated murine microglia. Furthermore, the DPPH-generated free radicals were inhibited by STE concentration-dependently.

Conclusion: STE has therapeutic potential in the prevention or treatment of neurodegenerative and oxidative stress-related disorders.